Polysiloxanes



Patented Aug. 22, 1950 POLYSILOXANES Stuart Dexter Brewer, Ballston Lake, N. Y., assignor. to General Electric Company, a corporation of New York N Drawing. Application September 13, 1947,

Serial No. 773,919

6 Claims. 1 This invention relates to novel chemical compounds and more particularly relates to linear hydrocarbon-substituted polysiloxane derivatives corresponding to the general formula I CH3 on, CH;

2- iO S lO- SiZ H Lt it where Z is the same and is a member of the class consisting of halogens and lower alkyl radicals, R is a member of the class consisting of hydrogen and lower alkyl radicals, and n is one of the following: O, 1.

Illustrative examples of lower alkyl radicals that Z and R in the above formula may represent are methyl, ethyl, propyl, isopropyl, butyl, etc. R and Z preferably contain from 1 to 2 carbon atoms. Among the examples of halogens which may be represented by Z are chlorine, bromine, fluorine, etc. Where Z is a halogen it is preferably chlorine.

It will be apparent from the above formula that where n is zero, the formula will then have the following structure:

CH3 CH1 where Z and R have the meanings given above in connection with Formula I.

The new compounds of this invention may be used as intermediates in the preparation of derivatives thereof. They are especially valuable in the preparation of synthetic condensation products, for example, in the preparation of linear oily compositions of matter useful for lubricating purposes. They may also b condensed with unsaturated hydrocarbons in accordance with the disclosures and teachings found in Krieble applications Serial Nos. 740,261-263, filed April 8, 1947, all of which applications are assigned to the same assignee as the present invention, the latter two of which are now Patent Nos. 2,510,642 and 2,479,374, respectively.

The halogen-terminated polysiloxanes embraced by the above Formula I may be made to react with thos reagents which are generally known to react with silicon-bonded halogen, e. g., I

oily hydrolysis product of methyldichlorosilane (CHsSiI-IClz) and a lower alkyl Grignard reagent wherein the alkyl group of the Grignard reagent is a member of the same class as specified for Z in Formula I.' Thereafter, the mixture is preferably treated with ice and dilute aqueous sulphuric acid. The ether solution which separates is washed with water, dried over a drying agent, for example, calcium chloride, and finally fractionally distilled to yield the desired products.

Where it is desired to produce halogen-terminated polysiloxanes corresponding to the above formula, reaction is efiected between the oily hydrolysis product of methyldichlorosilane and a lower alkyl-substituted dichlorosilane, for instance, methyldichlorosilane, in the presence of a small amount of a catalyst, for example, ferric chloride hexahydrate. The reaction is preferably conducted in a closed vessel provided with means for suitabl agitation. Fractional distillation of the reaction product yields the desired halogensubstituted polysiloxane. The method of preparation of the various compounds embraced by Formula I will become more apparent from the following examples which are given by way of illustration.

Example 1 About 730 grams of the isolated oily hydrolysis product obtained by hydrolyzing methyldichlorosilane was thoroughly mixed with 1300 grams (11.3 mols) methyldichlorosilane and 10 grams ferric chloride hexahydrate. The reaction vessel in which the mixture was confined was sealed tightly for 2 hours and shaken periodically. At the end of this time the reaction mass was fractionally distilled to yield 535 grams (3.06 mols) of 1,3-dich1or0-1,3-dimethy1disiloxane having the formula on; on;

ClSi-O 1-01 This compound has a boiling point of 104.0 C. at atmospheric pressure (about 754 mm.) and a density Analysis of the compound showed it to contain 40.49 per cent chlorine (calculated 40.48 per cent).

Continuing the fractional distillation described above, there was obtained 25 grams (0.11 mol) of 3 1,5 dichloro-l,3,5-trimethyl-trisiloxane having the formula.

Example 4 To a mixture of 13.5 grams (0.12 mol) 1,1,3,3- tetramethyldisiloxane and 22 grams (0.11 mol) CH; CH: CH:

I 1,3-diethyl 1,1,3,3 tetramethyldlsiloxane was C1 s|l-O 5 added 1 cc. of 95 per cent sulphuric acid. The H 1 mixture was shaken periodically for ,5 hour and thereafter washed with water ahd the resulting Thls compound the following properties: oil dried over potassium carbonate. Fractional and a distillation yielded the compound 1-ethyl-1,l,3,3- 27 10 tetramethyldisiloxane (also identified as 1,133- (1 tetramethyl-3-ethyldisiloxane) having the followin properties: Analysis of the compound showed it to contain 1'= 11 2,7'c 30.60 per cent chlorine (calculated 30.15 per 'n 13 79 cent). (14 0.78086 Example 2 R ,'0.3021(ca1c.0.3025) A solution of methyl magnesium bromide and Example 5 ,ethyl et er was p epa ed by addi a solu i o In this example 1,3-dichloro-1,3,3-trimethyldi- 1325 grams (13.9 mols) ofin'iethyl bromide in 630 mm v y -u grams diethyl ether to 334 grams (l 3. mols) of OH] magnesium metal. To this solution was added I w 711 grams (11.8 mols) Qfa liquid, oily polymeric methylsilox ane obtained by hydrql yzi n methyl: dichlorosilane. Thereaction mixture was allowed to'stand for about 24 hours and was then mixed z i g P f A iz i g fi f with ice and sufficient diluteaqueous sulphuric grams S) bf me Y1 and 22 grams octamethylcyclotetrasiloxane to- 995 ,1 P 2 3 gether with 2 grams -fe rric chloride hekahydrate 858m" h ether Solution which Separated was placed in a reaction vessel which was tightly F ht i t i 9Q. to femov residual a and stopped and sealed. This mixture was allowed a driedpver a c l e e h to Stand for 90 minutes at 20 0. Thereafterlt jr o .by distillation a d, th 'f's q wa was fractionally distilled to yielda incumbentreated with concentrated sulfuric acid tocozn- 3 ing at 122 C. which was identified at 1,3-dlplte the dehydration of 'silanols. The sulfuric chloro-1,3;3-trimethyldisiloxane. This compound at-m was removed, the residue washed, and the was found by analysis al ,:P Cent :resi due fractionally distilled to yield the foIlo'wchlorine (calculated 37.49 per cent). The comin compositions of matter haying the desigp d d-a natedpmperties: 40 (1% 1.058

v 1 D Hyd1g1 lgndod Polysiloxane B. P my" ID." to Silicon Found Calc. Found 0010.

. 1;1,3,3-Tetramethyldisilorane; 715s :1.:30e4- 0. 7504 0.2986 0.2993 1.51 1.50 ntamethyldisiloxane"; ..s0..0. 1.3739. 0.1599 0.3005 0.3005 0.68 0.08 examethyltrisiloxane 130 132; 173802 0.8203 0.2824 0.2824 098- 0.97

1 '1,113,5,0;5-hexamethyltrisiloxane.

Example 3 From the foregoing 'eziamples it will h'e apparent 1 7 to those skilled in the art that other anemic-a1 An Qther sotutlon i e h l a e l P miq compounds embraced by the general formula disw s Pr e m the 31 Ff EQFe P m closed in the first paragraph of this application Et Q 9 5 mFigPQ I s l f a may 'be prepared by the procedures er'nplo'yed in grams (2 mols) ethyl q To i 9 9 the preparation of the previously described and added ether t q of the i isolatedcheniical compounds. Among such como1ly hydrolysis product of 'methyl dichlorosilane. pounds may be mentioned m The mixture was treated with aqueous sulphuric prdpyldisiloxaney ;3;g; g y a d and the ether S0111ti0n, which D trisiloxane, pentabutyldisiloxane, 1j3- dibrom'orated from the water phase, was Washed thor- -1,3 dipropyldisiloxar1e, 1,5-dichl0ro- 1,3 .3,5-ttrafoughly and dried. Fractional distillation or the methyltrisiloxane, 1-,5-dibromo-1,3,3,5;5 pentaresidue yielded the following compounds: 05 methyltrisiloxane, etc.

n" Z Hydrgg i l gnded Polyslloxane B. P 111)" Di to Saloon Found Cale. Found 0510.

1'l,3-diethy1-l,3-dimethyldisiloiane-; 126.6 13972 0.7946 0.8032 0.3037 1.26 1.23 l';5-' iiethyl l;3,5-trimethyltrisi1oxane;; deal-164:4. 1.4001 "0.8376 0. 2899 0.2859 1.28 1.35

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Chemical compounds corresponding to the general formula A Lil it where Z is the same and is a lower alkyl radical containing from one to two carbon atoms, R is a.

6 member of the class consisting of hydrogen and lower alkyl radicals, and n is one of the following: 0,1.

6. The process which comprises (1) eifecting reaction between the oily hydrolysis product of methyldichlorosilane and methyl magnesium bromide in an ethyl ether medium and (2) fractionally distilling the reaction product to obtain pentamethyldisiloxane.

STUART DEXTER BREWER. I

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number i Name Date 2,381,366 Patnode Aug. '7, 1945 2,386,441 Daudt Oct. 9, 1945 2,421,653 Sauer June 3, 1947 OTHER REFERENCES Patnode et al.: Jour. Amer. Chem. Soc., vol. 68 (1946) pages 3584363.

Rochow: Chemistry of the Silicones, page 37, published in 1946 by John Wiley 8: Sons. 

1. CHEMICAL COMPOUNDS CORRESPONDING TO THE GENERAL FORMULA 